Level, Higher and Lower

A higher position is farther up, away from the center of the Earth, relative to sea level. Conversely, a lower position is closer toward Earth’s center, relative to sea level. Two positions are level if they are at the same height from sea level.

Some flat-Earthers are unable to understand this. To them, ‘level’ means straight. They are wrong. In Earth sciences, height is measured from a plane of reference, usually the sea level.

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Proofs of Spherical Earth Presented by Flat-Earthers

Many adherents of flat Earth have spent a lot of effort and money to perform various observations and experiments. They would buy expensive equipment, travel to the other side of the world, painstakingly designed the experiments in minute details, and performed large-scale experiments; all to prove the notion that Earth is flat. However, many of these experiments and observations have actually confirmed the Earth is a sphere beyond any doubt.

In most cases, they would not accept such conclusions, and instead, they misinterpret, refuse to accept, lie, and withhold information. Such behaviors are the results of confirmation bias. However, their results speak louder than their biased conclusions, and these are perfectly valid proofs that Earth is a sphere.

These are some of those observations and experiments, where flat-Earthers have painstakingly and extravagantly performed them, only to come up with the wrong conclusions and spectacularly demonstrating their confirmation biases to the entire world.

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The Varying Continent Sizes in Different Images of Earth from Space

The amount of Earth’s surface we can see at once from a location in space depends on our distance to the Earth. The closer the observer, the smaller the amount of visible Earth’s surface. Conversely, the farther the observer, the larger the amount of Earth’s surface visible to them. But no matter how far the observer, they would not be able to see the entire hemisphere.

Flat-Earthers discovered that there are the differences in the sizes of continents in the different images of the Earth, and used the fact as ‘evidence’ of misconduct. They are wrong. Such differences in continent sizes are present because the images show the Earth from different distances and different field of view.

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Buoyancy is an upward force exerted by a fluid (liquid or gas) that opposes the weight of an immersed object. Buoyancy happens because the fluid has a pressure gradient. Pressure gradient occurs because the fluid is affected by acceleration, such as the Earth’s gravitational acceleration.

Flat-Earthers makes buoyancy as an “explanations” on how things fall. They are wrong. Without Earth’s gravitational acceleration, buoyancy will not occur.

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Ships Disappearing Over the Horizon and the Various “Explanations” Invented by Flat-Earthers

Due to Earth’s curvature, ships traveling over an ocean disappear from the bottom up. This fact is one of the first evidence to confirm the Earth is a sphere, and one of the first facts of which flat-Earthers had to invent various “explanations” for.

Some of the popular “explanations” are: refraction, perspective, zooming reveal distant ships and visibility limitations. None can explain away the fact.

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The Taiwan–Los Angeles Flight (not from Bali) that was Diverted to Anchorage

There was a flight from Taiwan to Los Angeles that was diverted to Anchorage because one of the passengers gave birth to a baby. Flat-Earthers use the case as one of the first “evidence” from flight routes proving Earth is flat.

They are wrong. The case only tells us about the ignorance of these flat-Earthers about the distortion in a map projection. Their argument started with an elementary mistake of taking a straight line on a Mercator map between Taiwan and Los Angeles, and assume it as the “intended flight path.”

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Geometry of Perspective

Perspective is a relationship between the size of an object, its distance, and its apparent/angular size. The angular size is larger if the object is closer or larger.

Often, flat-Earthers would claim that we cannot see a distant object is not the result of Earth’s curvature, but because of perspective. In a way, it is correct to say that perspective might result in an object having angular size too small to be seen by our eyes. However, perspective alone cannot ‘hide’ a portion of an object, while revealing the rest of it.

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Some flat-Earthers like to observe celestial phenomena and the positions of celestial objects. Sometimes, they insist such events cannot possibly happen if the Earth is a sphere orbiting the Sun, and took the wrong conclusion that the Earth must be flat.

We can try asking them the time of the occurrence and the position of the observer, then use Stellarium or similar applications to simulate it. If the result matches the observation, then they have nothing to complain about. Their confusion was only the result of their ignorance.

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The Lack of Motion Blur in Earth Photos

The surface of the Earth close to the equator is moving at the speed of about 1670 km/h due to Earth’s rotation. To take a sharp picture of the Earth with the resolution of 10000×10000 from a stationary position in space, it would require the shutter speed faster than 2.7 seconds. It is not difficult at all to take a sharp picture of the entire Earth without perceivable motion blur.

Flat-Earthers claim that it should be impossible to take a sharp picture of the Earth from space due to the speed of Earth’s rotation. To them, the fact that a photographer cannot take a sharp photo of a speeding race car from the sidelines (they actually can) tells us it should be impossible to take a sharp picture of the Earth moving at 10× the speed.

They are wrong. Motion blur is caused by the angular speed of the object relative to the camera, not from its absolute speed. The vast distance required to take a photo of the Earth results in a very low angular speed, making it not difficult at all to take sharp images of the Earth.

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How to “Prove” a Basketball (or any Spherical Object) is Flat

If we were to magnify the surface of any spherical object with large enough magnification, then at some point, it would appear flat. This can be easily demonstrated using a macro lens as the Redditor ‘Useless-Pickles’ did. He magnified the surface of a basketball using an extreme macro lens as a philosophical demonstration.

This shows that the surface of a spherical object can easily look flat if the object is large enough, or the observer is small enough.  And the basis of all flat-Earthers’ belief that the horizon appears flat is insufficient to determine the shape of the Earth. By applying the same “logic” as these flat-Earthers, we can actually “prove” a basketball is flat, which, as we all know, is clearly wrong.

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Auguste Piccard, Another Scientist Falsely Claimed by Flat-Earthers

Auguste Piccard was a Swiss-Belgian physicist, inventor, and explorer, known for his record-breaking balloon flights to the stratosphere, as well as the invention for bathyscaphe to allow for deep ocean exploration.

Unfortunately for him, flat-Earthers are claiming him as their own these days. It started from a Popular Science article from 1931, saying:

Through portholes, the observers saw the earth through copper-colored then bluish, haze. It seemed a flat disk with upturned edge.

But, no. In reality, Auguste Piccard was not even close to being a flat-Earther.

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Lens Flare, Not a Mysterious Celestial Body

A photograph of an object does not necessarily look the same as the real object. There are various optical imperfections, which are impossible to avoid by both the designer of the optical system and the photographer taking the picture. One of those imperfections causes lens flare.

Some flat-Earthers noticed the existence of a ‘mysterious celestial body’ next to a photograph of the Sun or the Moon. They would use such sightings to ‘explain’ various celestial phenomena which cannot be readily explained in the flat Earth model, like eclipses. They are wrong. The ‘mysterious celestial body’ was merely a lens flare.

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Suez Canal

The Suez Canal is a waterway connecting the Mediterranean Sea to the Red Sea. The level of water on both seas is practically the same, and the Suez Canal contains no locks system.

Flat-Earthers are claiming that the Suez Canal was constructed without accounting for curvature. They said if the Earth were spherical, then the middle of the canal should have been 1666 ft deep. This is merely a misconception. The surface of the water is equipotential. It has roughly the same distance to the Earth’s center of gravity. It is not necessary to dig 1666 ft in the middle of the Suez Canal. The engineers only need to ensure the base of the canal is below sea level for sea water to flow.

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Circular Reasoning

Circular reasoning is a logical fallacy in which the proposition is supported by the premises, which is supported by the proposition, creating a circle in reasoning where no useful information is being shared.

Flat-Earthers often commit the fallacy of circular reasoning to defend the notion that the Earth is flat. Such reasoning is never useful, and cannot be regarded as evidence of anything, despite what they are claiming.

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Sunrays are Practically Parallel, but not Perfectly Parallel

The Sun emits sunrays to every direction. But as the Sun is very far, the sun rays that reach us are practically parallel. To an observer on Earth, the rays of light coming from the Sun form a maximum angle of about 0.53°. They are practically parallel, but not perfectly parallel.

Flat-Earthers often question the fact we say sun rays are parallel, but in any diagram of an eclipse, they are drawn at an angle. They merely confuse practicality with perfection. Sunrays are practically parallel, but they are not perfectly parallel.

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